SQL HAVING Clause | Filtering Grouped Data

SQL HAVING

We already know that the WHERE clause is used to filter records. But there is a limitation. WHERE works on individual rows, not on groups.

Now think about questions like:

These conditions are applied after grouping and aggregation, not before. This is where the HAVING clause becomes necessary.

What Is the HAVING Clause?

The HAVING clause is used to filter grouped results after the GROUP BY clause has been applied.

WHERE filters rows, HAVING filters groups.

When Do We Use HAVING?

HAVING is used when:

Syntax

SELECT column_name, aggregate_function(column_name)
FROM table_name
GROUP BY column_name
HAVING condition;

Example: employees Table

id	name	salary	department
1	Amit	60000	IT
2	Neha	75000	HR
3	Rahul	50000	IT
4	Priya	90000	Finance
5	Karan	45000	HR

Example - 1: Departments with Total Salary Greater Than 1,00,000

Problem: Show only those departments whose total salary exceeds 100,000.

SELECT department, SUM(salary) AS total_salary
FROM employees
GROUP BY department
HAVING SUM(salary) > 100000;

HAVING filters departments after grouping.

Why WHERE Cannot be Used Here

This will cause an error

WHERE SUM(salary) > 100000

Reason

WHERE cannot work with aggregate functions.

Example - 2: Departments with More Than One Employee

SELECT department, COUNT(*) AS employee_count
FROM employees
GROUP BY department
HAVING COUNT(*) > 1;

Only departments having more than one employee are shown.

HAVING with WHERE

Execution Order

1. WHERE - filters rows

2. GROUP BY - groups rows

3. Aggregate functions - applied

4. HAVING - filters groups

5. ORDER BY - sorts final result

Example: IT Department with Average Salary Above 55,000

SELECT department, AVG(salary)
FROM employees
WHERE department = 'IT'
GROUP BY department
HAVING AVG(salary) > 55000;

WHERE filters rows first, HAVING filters grouped result.

Common Use Cases of HAVING

Difference Between WHERE and HAVING

Important Points About HAVING

Two Minute Drill